Enumeration of Genetic Variability Parameters and Diversity Analysis among Mutant Genotypes of Indian Mustard [Brassica juncea (L.) Czern & Coss.]

The investigation was conducted during the rabi season (October–March) of 2019–20 and 2020–21 at the Agricultural Research Farm, Institute of Agricultural Sciences, BHU, Varanasi, Uttar Pradesh, India. The study aimed to evaluate Indian mustard mutants for variability and diversity using various quantitative traits. Twenty mutant genotypes, along with the national check Kranti, were grown in a randomized complete block design with three replications, observing 17 quantitative traits. Combined ANOVA indicated significant genotypic differences for all traits, while genotype×environment interaction was non-significant, except for seeds siliqua-1. Most traits exhibited moderate genotypic and phenotypic coefficients of variation, while days to maturity, number of primary branches, siliqua length, seeds siliqua-1, and chlorophyll content had low genotypic coefficients of variation. High heritability was observed for traits such as the length of the main raceme, number of secondary branches, days to 50% flowering, number of siliqua plant-1, and test weight. Traits like the number of secondary branches, length of the main raceme, number of siliqua plant-1, seed yield plant-1, test weight, and yield ha-1 had high genetic advance as a percentage of the mean, while days to maturity, siliqua length, and seeds siliqua-1 had low values. Tocher’s method grouped the genotypes into five clusters, with the highest intra-cluster distance in cluster III (9.15) and the highest inter-cluster diversity between clusters I and V. Principal component analysis identified six components explaining 82.46% of the total variability, with PC1 contributing 28.39% and PC2 accounting for 15.66%.